Liquid crystalline geometrical phase Alvarez-Lohmann lenses

Thin-film LC based geo-phase optics have previously been demonstrated to drastically reduce size, weight, and power requirements for large-aperture optical systems while providing non-mechanical functionality for discrete values – for example, digital switching of the beam steering angle. In this work, we present a series of geo-phase Alvarez-Lohmann lens systems capable of analog tuning of focal length through lateral translation or azimuthal rotation. For circularly polarized inputs, diffraction efficiencies greater than 90% were observed over the visible spectrum with some wavelengths exceeding 99% for lateral embodiments. Both cylindrical and spherical Alvarez-Lohman systems were fabricated with focal lengths varying from infinity to 110 mm with increasing lateral displacement. These LC-based geo-phase optical systems could enable a new generation of low-cost, high-performance, and ruggedized dynamic optical components.